Method for Manufacturing Artificially-Structured Protein Fiber

Abstract

An object of the present invention is to provide a method for producing an artificial structural protein fiber having a small diameter and having a stress equal to or higher than that of the related art. A method for producing an artificial structural protein fiber according to the present invention is a method for producing an artificial structural protein fiber by a wet spinning method, the method including a coagulation step of discharging a spinning dope containing an artificial structural protein and an organic solvent from a spinneret into a coagulation liquid to coagulate the artificial structural protein, wherein a bath draft in the coagulation step is more than 0.4 and 20 or less.

1 . A method for producing an artificial structural protein fiber by a wet spinning method, the method comprising a coagulation step of discharging a spinning dope containing an artificial structural protein and an organic solvent from a spinneret into a coagulation liquid to coagulate the artificial structural protein, wherein a bath draft in the coagulation step is more than 0.4 and 20 or less. 
     
     
         2 . The method according to  claim 1 , wherein the coagulation liquid contains water or an aqueous solution having a pH of 0.25 or more and 10.00 or less. 
     
     
         3 . The method according to  claim 2 , wherein a content of the water or aqueous solution having a pH of 0.25 or more and 10.00 or less in the coagulation liquid is 70% by mass or more based on 100% by mass of a total amount of the coagulation liquid. 
     
     
         4 . The method according to  claim 2 , wherein the aqueous solution is at least one type selected from the group consisting of a sulfate aqueous solution, a chloride aqueous solution, a carboxylate aqueous solution, a hydrogen phosphate aqueous solution, a bicarbonate aqueous solution, brackish water, and sea water. 
     
     
         5 . The method according to  claim 2 , wherein the aqueous solution is at least one type selected from the group consisting of a sodium chloride aqueous solution, a sodium sulfate aqueous solution, and a sodium citrate aqueous solution. 
     
     
         6 . The method according to  claim 1 , wherein a content of the artificial structural protein in the spinning dope is more than 10% by mass and 50% by mass or less based on 100% by mass of a total amount of the spinning dope. 
     
     
         7 . The method according to  claim 1 , wherein an average hydropathy index of the artificial structural protein is more than −0.8. 
     
     
         8 . The method according to  claim 1 , wherein the artificial structural protein contains at least one type selected from the group consisting of a spider silk fibroin, a silk fibroin, and a keratin protein. 
     
     
         9 . The method according to  claim 1 , wherein the artificial structural protein is a spider silk fibroin. 
     
     
         10 . The method according to  claim 1 , wherein the artificial structural protein is a modified spider silk fibroin. 
     
     
         11 . The method according to  claim 1 , wherein the organic solvent in the spinning dope is at least one type selected from the group consisting of formic acid and hexafluoroisopropanol. 
     
     
         12 . The method according to  claim 1 , wherein the coagulation liquid contains the organic solvent, and a content of the organic solvent in the coagulation liquid is 10% by mass or more and 30% by mass or less based on 100% by mass of a total amount of the coagulation liquid.